Used in increasing measure for the production of electronic circuits are substrate plates made of ceramic materials, glass, or of semiconductor materials, which are provided with circuit patterns lying in superimposed relationship one over the other in one or several layers. This requires one or several light exposure procedures in which the substrate plate is, each time, illuminated through a mask whose pattern corresponds to the desired circuit pattern in the plane concerned. A basic assumption for the production of a satisfactory, sharply illuminated pattern on the substrate plate is an exactly plane-parallel adjustment of the substrate plate relative to the light or illumination exposing mask prior to exposure. In an older state of the art, this occurred by moving the substrate plate, while arranged on the wedge error correction head, close to the light exposing mask up to the point of full surface contact between substrate plate and exposing mask. Accordingly, the desired plane-parallel adjustment results in positive fashion. With this adjustment, illumination took place either at the same time, or the adjustment of the wedge error correction head was fixed in the contacting position of substrate plate and light exposing mask, and thereafter the wedge error correction head was moved a slight distance away relative to the light exposing mask, and the calibration of the pattern on the light exposing mask to the pattern on the substrate plate was carried out from this remote position. Illumination occurred after the contact between mask and substrate was re-established.
However, since the surface of the substrate brought into contact with the light exposing mask is not at all smooth, displaying rather a very high degree of micro-roughness, the light exposing mask is somewhat degraded or marred with each parallelizing procedure, so that the relatively expensive light exposing mask had to be replaced after about 40 illuminating procedures.
The present invention emanates from a more developed state of the art ("Micro Electronics", Volume 6, No. 4, 1975, pages 51-59), where, for parallelizing, the substrate plate need no longer be brought into surface contact with the light exposing mask. Moreover, for parallelizing of substrate plate and light exposing mask, there is introduced between these two elements a disk-shaped parallelizing gauge with a rim bead running about it that displays a very constant axial thickness and projects out to both sides, in the axial direction, over the enclosed disk surface. By moving the substrate plate closer to the light exposing mask, there now results a placement, each in turn, of one outer circumferential area of the substrate plate and of the light exposing mask against the oppositely facing front surfaces of the rim bead of the parallelizing gauge. This makes possible a satisfactory plane-parallel adjustment of the substrate plate relative to the light exposing mask, without having the two elements touching each other (except for a negligibly narrow rim area which is of no consequence). However, in order for it to be able to be pushed, via a slide, between the substrate plate and the light exposing mask without drooping and without scraping, the disk-shaped parallelizing gauge must display a considerable thickness that is essentially greater than that interval between substrate plate and light exposing mask, that is still just permissible, during the illuminating procedure (with too great an interval between substrate plate and light exposing mask, fuzzy or non-sharp illuminations result). Consequently, after parallel adjustment of substrate plate and light exposing mask, the substrate plate must be moved sufficiently far away from the light exposing mask, by appropriate axial movement of the wedge error correction head, in order that the parallelizing gauge can be withdrawn without damaging the side surfaces of substrate plate and light exposing mask, whereafter the substrate plate must again be moved close to the light exposing mask, up to the small distance required for illuminating. However, the axial movements of the wedge error correction head required for this can be carried out only at a relatively slow speed, since, in each case, impingement of the substrate plate on the light exposing mask must be avoided. These slow speeds in turn occasion a very important expenditure of time.